1. Field of the Invention
This invention relates to a door assembly which is provided in a recording and reproducing apparatus for closing an opening through which it is loaded with a recording medium.
2. Description of the Prior Art
There is known an external storage device for storing data or programs which can be used in a central processing unit. The device is under the control of the central processing unit, but is not necessarily combined therewith permanently. More specifically, there is, for example, a disk drive device which rotates a magnetic or optical information recording medium in the form of a disk for recording or reproducing information. A small disk drive device is mainly used for a personal computer or a word processor. There is also a smaller device which is used for driving a still video floppy disk.
A system in which a disk drive device is incorporated usually has a front panel of the type which is shown by way of example at 1 in FIGS. 13 and 14. The front panel 1 has a slot 2 through which a disk cartridge, i.e. a hard case containing, for example, a magnetic disk is inserted. A swinging door 3 is provided behind the slot 2 as shown in FIG. 14. The door 3 is rotatably supported on a shaft 4 extending horizontally along the upper edge of the slot 2. A spring 5 is provided on the shaft 4 for urging the door 3 downwardly so that it may close the slot 2. The front panel 1 is usually supported on a sidewall 6 of the disk drive device, or on that portion of a system housing in which the disk drive device is mounted. The front panel 1 also has a hole 7 (FIG. 13) through which an eject lever not shown projects from the disk drive device.
The door 3 is provided for closing the slot 2 to shut out dust when the disk drive device is not used. When the device is loaded with a disk cartridge, the door 3 can be pushed open by the cartridge. When the device has been loaded, however, the lower edge of the door 3 rests on the disk cartridge and is not lowered to the level which enables the closure of the slot 2. Therefore, there is every likelihood that dust may enter the disk drive device as long as it contains the cartridge.
This problem ca be overcome if the disk cartridge which has been inserted through the slot 2 can be lowered to a level which enables the door 3 to swing to its closed position. However, an increase in height of the device is required to provide a space in which the disk cartridge can be satisfactorily lowered and a mechanism which is required for lowering the cartridge complicates the device. These factors are undesirable from the standpoints of compactness in construction and cost reduction. There is another problem, even if the door can be closed when a disk cartridge has been placed in the disk drive device. When the door is in its closed position, it is impossible to know if the device contains a disk cartridge. There is every likelihood of erroneous operation. These problems are particularly prominent with respect to a still video camera, a cassette deck or compact disk drive unit for use in a vehicle, etc. Therefore, there has been a strong demand for a device which is highly dustproof and free from any possibility of erroneous operation irrespective of the environment in which it is used.